Genetically based trait coordination and phenotypic plasticity of growth, gas exchange, allometry, and hydraulics across the distribution range of Pinus pinaster

Studying intraspecific trait variation across environments is key for understanding how resource-use strategies evolve. It is hypothesized that plants from mesic environments have evolved toward a more acquisitive strategy with high growth potential and phenotypic plasticity, while populations from xeric continental climates exhibit a conservative strategy with slower growth and better physiological performance under drier conditions. We tested this hypothesis through the phenotypical characterization of 14-yr-old Pinus pinaster Aiton trees from 20 range-wide populations growing in two climatically contrasting common gardens. We measured 20 traits related to growth, leaf morphology, gas exchange, photochemistry, and hydraulics. Consistent with our hypothesis, we found that populations from mesic oceanic areas exhibited higher growth rates and higher allocation to leaf surface area under mesic conditions, along with greater plasticity in these traits. By contrast, xeric continental populations had better physiological status, showing higher gas exchange rates and photochemical efficiency, but lower sapwood-specific hydraulic conductivity under drier conditions. Together, our results provide evidence that climate drives the joint evolution of leaf and stem traits and their plasticity following an acquisitive-conservative axis of resource use. Overall, trait coordination is found to be highly plastic, likely to maximize plant performance under contrasting environmental conditions.

This study was funded by the Spanish Ministry of Science, Innovation and the EU Resilience and Recovery Mechanism through the competitive grants PID2021-126399NB-I00 and TED2021-129570B-I00 awarded to JAR-V. JAR-V was also supported by a research contract financed by the AEI (Spanish Research Agency) and Ministry of Science through the Severo Ochoa Program for Centres of Excellence in R + D + I (CEX2018-000828-S). This work was also supported by SGR-RESET project (ref.: 2021 SGR 00849): Biogeografia funcional i RESiliència d'Ecosistemes Terrestres (CREAF/UAB). SCG-M was supported by the European Union's Horizon 2020 research and innovation program under grant agreement no.: 101081774 (OptFORESTS). FJC-M acknowledges grant RYC2021-035064-I funded by MCIN/AEI/ 10.13039/501100011033 and ‘European Union NextGenerationEU/PRTR’.

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2018-000828-S)

Peer reviewed